Frank Harold Spedding (22 October 1902 – 15 December 1984) was a Canadian chemist. He was a renowned expert on rare earths and on extraction of metals from minerals. His uranium extraction process helped make it possible to build the first atomic bomb.

After graduation he worked at UC Berkeley and Cornell University. In 1937 he became an assistant professor and head of the department of physical chemistry at Iowa State University in Ames, Iowa. He was named a professor of chemistry in 1941, a professor of physics in 1950, and a professor of metallurgy in 1962.

He did pioneering work on rare earths and was "universally acknowledged as one of the world’s foremost experts on the identification and separation of rare earths".[1] He developed an ion exchange method of separating and purifying rare earth elements using ion exchange resins.

In 1941 he was asked to work on the research which later became known as the Manhattan Project and led to the development of the atomic bomb. He led a group of chemists at Iowa State University which developed an efficient process (known as the Ames process) for obtaining high purity uranium from uranium halides. Between 1942 and 1945 this process was used to produce two tons of pure uranium. Spedding was present at the University of Chicago to witness the first controlled atomic chain reaction.[1]